class Student:
    count=0
    __tax_discount_rate=0.1

    def __init__(self,name,age,sex,fee,is_married):
        self.name=name
        self.age=age
        self.sex=sex
        self.__fee=fee
        self.__is_married=is_married

        Student.count+=1

    def display_student(self):
        print("姓名：%s,年龄：%d,性别：%s"%(self.name,self.age,self.sex))

    def display_fee(self):
        print("%s的学费为%f"%(self.name,self.__fee))

    def __get_is_single(self):
        if self.__is_married:
            return False
        else:
            return True

    def get_tax_return(self):
        if self.__get_is_single():
            return self.__fee*Student.__tax_discount_rate
        else:
            return 0.0

    def display_tax_return(self):
        print("%s的退税额度为：%f"%(self.name,self.get_tax_return()))


if __name__=='__main__':
    student_1=Student("范淼",29,"男",5000.0,False)
    student_2=Student("刘晓龙",34,"男",5500.0,False)

    student_1.display_student()
    student_2.display_student()

    print("目前学生总数为%d人"%Student.count)

    student_3=Student("孙华枭",28,"男",5600,True)
    student_4=Student("陈蓓",27,"女",4500,True)

    print("目前学生总数为%d人"%Student.count)

    student_1.display_tax_return()
    student_3.display_tax_return()

